Trunk floor replacement

It may or may not be easier on you if you remove the axle & springs, but if it won't take you long it could be worth the effort when you have to get underneath to trace the frame rail lines on the bottom of the new pan. You will need to do that in order to know where to drill holes in the pan, to weld thru. As long as the quarter panels and rear crossmember that the back bumper bolts to are still in place, it shouldn't move much, if any. If it were me, I would support the frame rails before you remove the old metal as an extra precaution. Getting the new pan to fit against the taillight panel will be the hardest part, plus the trunk lock support. All of that sat on top of the trunk floor that was welded in first.